The psychological need of someone to close down the window shutters, dim the lights, turn off the phone, eat junk food, surf on the internet, watch TV, listen to music and use drugs, remaining in this condition for few hours, days or weeks, into her/his flat, denying to go out or to meet anybody, like she/he is hiding into her/his own cave. Strongly connected to Minor or Major Depression and Agoraphobia.

A: Man, I haven't seen Matthew for ages! Where has he been?
B: He hasn't been out of his house for a good two weeks now, isolated, eating pizzas and smoking weed...
A: Holy molly, he's caving again...